1. Technical Field of the Invention
The present invention relates to a sputtering apparatus whereby film deposition is performed in vacuum on to a semiconductor wafer or disk such as a CD or DVD.
2. Description of Prior Art
An example of a prior art sputtering apparatus disclosed in Japanese Laid-Open Patent Application No. 7-102366 will be described with reference to FIG. 7. In FIG. 7, a substrate 60 is mounted on a substrate holder 63 which is arranged fixed to a door 62 of chamber 61, and a cathode 64 is arranged so as to face substrate holder 63. A shutter plate 65 is arranged in a retractable manner between substrate holder 63 and cathode 64. A sputtering power source 66 applies voltage to cathode 64. A vacuum evacuation port 67 is provided on one side of chamber 61 and a gas introduction port 68 is provided on the other side for introducing sputtering gas. An earth shield 69 is arranged around cathode 64, and a shield 70 is provided such as to surround the peripheral part of substrate holder 63.
For film deposition, door 62 is opened and a substrate 60 is held on substrate holder 63; door 62 is then closed and vacuum evacuation is performed from vacuum evacuation port 67 and sputtering gas is introduced from gas introduction port 68 whilst maintaining the interior of chamber 61 at a predetermined vacuum pressure; a sputtered film is formed on substrate 60 by applying negative charge to cathode 64 by means of sputtering power source 66. After this, the interior of chamber 61 is returned to atmospheric pressure, door 62 is opened, substrate 60 on which the film has been formed is removed, and a substrate on to which film is to be deposited is supplied to substrate holder 63.
Such sputtering apparatuses are used on account of their low equipment cost, simplicity and suitability for batch production.
However, in such sputtering apparatuses, since vacuum evacuation and opening to the atmosphere are repeated every time film deposition is performed, the processing efficiency shows considerable dependence on the time required for vacuum evacuation to the background vacuum pressure for sputtering. However, with the sputtering apparatus of conventional construction, time is required for the vacuum evacuation since, in particular, vacuum evacuation of the interior space is obstructed by shield 70 which is arranged surrounding the peripheral part of substrate holder 63 in what is close to a sealed condition; there was therefore the problem that processing efficiency was adversely affected.
A further problem was that in the conventional sputtering apparatus consideration was not given to the automation of mounting and removal of the substrate and it was not possible to improve production efficiency.